This invention relates to an improved lamp for use in vehicles and beacon lights and so forth. The conventional lamp for use as beacon lights or for illumination, especially in vehicles is shown in FIG. 1 and comprises a housing containing a bulb, an inner lens having so-called frenel lens which converts the light radiated from the bulb into parallel rays of light, and a condenser lens consisting of a plurality of convex lenses on the surface facing the bulb. The condenser lens condenses the parallel rays of light into a plurality of beams, so as to make the beams pass through the light pervious portions which are disposed on an outer lens, as shown in FIG. 1. In the conventional illumination lamp, it is generally required to radiate the light as far as possible without causing its luminous intensity to be weakened, and for this purpose there have been many kinds of improvements. However, when the light emitted by the bulb is converted into parallel rays of light and the parallel rays of light are condensed at the focal point between a condenser lens 1 and a slit 2 as shown in FIG. 1, the diffusion of the light will become greater as it goes away from the focal point, weakening the luminous intensity. The disadvantage is that the light is unable to be seen from a distance. Moreover, if the lamp is thus constructed, the light emitted by the bulb will not be emitted out of the slit 2 at 100% effectiveness unless the location of the slit 2 is arranged at a point which corresponds to the focal point of the condenser lens 1.